This invention relates to a remote indicating magnetic compass. It is a particular object of our invention to derive the magnetic heading of an object or vessel by means independent of stray magnetic fields, nearby ferrous objects and the pitching, rolling and yawing of the location at which the compass is used to an extent hereinbefore unattainable in terms of convenience, accuracy and cost, for reasons including the type of sensor, its remote positioning where desired from the reading position, the electronic detection means and subsequent depiction, digitally, in numerical degrees and/or by analog means, employing points of light on the surface of a screen, cathode ray tube or other area representing the relative positions of the north direction and that of the object whose heading is required.
It is well known that the needle of a conventional magnetic compass is influenced by magnets, magnetic materials or the fields generated by electric currents in the vicinity of the conventional compass. This is especially troublesome in the case of a powerboat or aircraft when it is desirable to have the compass located on the dashboard close to other instruments which normally include strong permanent magnets such as fuel gauges, ammeters, speedometers, tachometers etc.
Further types of deviating influences to correct alignment of the conventional magnetic compass needle include the multiple irregular shocks and vibrations caused by a fast vehicle as it proceeds over a wavy surface such as the stormy sea or air, so that elaborate means of damping and suspension have to be employed, which do not eliminate, only improve inaccuracies of the readout.
Several magnetic compass systems are known which solve both the aforementioned problems, but at prohibitive cost as regards small commercial or pleasure craft. In the Sperry Gyroscope "Gyrosyn" compass, the sensor of the earth's magnetic field called the "Fluxvalve" is located in a suitable spot at the wing of an aircraft well away from the dashboard with its strong magnetic fields and is used to control a gyrowheel as a repeater in view of the pilot. Several patents have been granted for variations of the "Fluxvalve", however all are relatively expensive and elaborate for small commercial and non-commercial applications.